The present invention relates to detector systems for chemical and biological sensing. The present invention also relates to small form factor, portable, handheld and wearable detector systems and in particular to portable, handheld and wearable detector systems including sensor arrays configured for biological and chemical analyte detection, and which are configurable with software modules to detect and analyze a variety of environmental conditions and which have low operating power requirements and long lifetimes.
Civilian and military personnel, Coast Guard and Customs, State and Federal Emergency Responders, and Industrial Workers would greatly benefit from a personal early-warning system to identify changes in environmental conditions, such as the release of hazardous airborne chemicals or biological agents, in time to either evacuate or don protective equipment, such as chemical protective equipment (CPE). For example, releases of toxic industrial chemicals (TICs) may occur accidentally in the course of normal operations, from unseen leaks in fueling, heating or cooling systems, or from intentional hostile actions. Additionally, chemical warfare agents (CWAs) and biological warfare agents (BWAs) may be released during combat or in other potentially hostile situations such as during terrorist activity. Each of these situations presents a unique and potentially broad range of chemical and biological threats that typically cannot be identified a priori. There is a need to detect and characterize TICs, CWAs, BWAs and other environmental conditions before hostile exposure in order to take appropriate actions to neutralize the threat. A similar need exists after a TIC, CWA or BWA release to identify the chemical or biological agent class such that appropriate defensive and decontamination measures may be taken.
While laboratory instruments with high specificity and accuracy are available, they are not generally suitable for field use because they lack physical robustness, require highly trained operators, and typically are not portable due to size, weight, high power consumption requirements, and chemical reagent (gases, liquids) requirements. In addition, specialized portable instruments for one threat type, (e.g. CWA) may not work for the other threat types of interest, (e.g. explosives, fire, BWAs or TICs) or for improvised devices.
Handheld as well as wearable, passive detectors for hazardous conditions such as TICs, BWAs and CWAs will greatly improve the safety of the personnel operating in threatened environments. Useful known portable detectors include point detectors and standoff detectors. One chemical point detector, the Joint Chemical Agent Detector (JCAD), is hand held and portable but has a limited operational life on a single charge, requiring frequent recharging. In addition, the JCAD has to be handled impairing use of other devices simultaneously. Standoff detectors, such as the Joint Services Lightweight Standoff Chemical Agent Detector (JSLSCAD), can continuously protect personnel from CWAs, but (1) lack spatial resolution and (2) have detection limits much larger than the Immediately Dangerous to Health and Life (IDLH) level. General limitations of current badge or wearable detectors (e.g., SafeAir, ToxiRAE) include: 1) analyte-specificity: these require detailed a priori knowledge of chemical hazards, or multiple badges for broad spectrum coverage, and cannot detect new or unknown hazards; 2) single-use: disposable detectors and dosimeters require re-supply for continuous protection; 3) interpretation errors: colorimetric indicators require visual comparisons (color cards) that are prone to user subjectivity; 4) no alarm modes or communications capability: these do not provide rapid hands-free warning or transmission of status; 5) environmental performance: extremes of temperature (e.g., <0° or >40° C.) and humidity (e.g., <10% or >90% relative humidity (RH)) limit some sensors (e.g., electrochemical, conducting polymers). Such detectors also do not typically include datalogging capability (e.g., storing detailed historical information/records of the environment encountered), or may only provide a time-averaged history of exposure. Additionally, current detectors also typically have high operational power requirements and, therefore, typically short operational lifetimes. For example, the JCAD requires recharging or replacement of the power supply every 20 hours or less.
Some sensor devices, such as the ToxiRae Plus, produce audible and vibratory alarns, eliminate interpretation errors, and have datalogging capability, but these wearable sensors are still analyte-specific. In addition, these sensors are not useful as badge detectors since they require a pocket or belt clip due to their size and weight.
Wearable sensor devices with analyte-general capability have been developed, e.g., by EIC Laboratories, Inc. and Physical Sciences, Inc., however these devices have significant performance issues with humidity that are likely to affect the ruggedness and stability of the sensors during field-use of the badge detector.
While improvements have been made in the field of chemical and biological sensing, the diverse set of potential target compounds and numerous sensing methodologies has limited progress. Most current low-cost sensors are based on a single sensing approach optimized to detect one, or a class, of compounds.
On the biological side, significant recent research has been directed toward fluorescence-based arrays for genomic and proteomics applications (Kristensen et al., Biotechniques, 30(2):318 (2001); Harrinton, et al., Curr. Opin. Microbiol, 3(3):285 (2000); Katsuma et al., Expert Rev. Mol. Diagn., 1(4): 377 (2001); Templin et al., Trends Biotechnol, 20(4):160 (2002); Schweitzer et al., Curr. Opin. Biotechnol, 13(1):14 (2002); Gabig et al., Acta Biochim. Pol., 48(3):615 (2001); Weinstein et al., Cytometry, 47(1):46 (2002)). These arrays all focus on a single sensing approach, most often related to binding of a fluorescent probe. Because of the complex nature of reading and interpreting these arrays, they are always associated with laboratory based analytical instruments and are not compatible with widely distributed sensing networks.
While high density sensor arrays have recently been developed for biological detection, these sensors often require a significant amount of wet chemistry prior to detection and are based on relatively complicated and expensive read out electronics such as optical readers. Furthermore, since these arrays rely exclusively on specific binding, these arrays are not effective chemical sensors and require a great deal of customization of each sensor element.
There is therefore a need for improved sensors and detector systems for biological and chemical sensing. There is also a need for personal detector systems (e.g., portable and wearable detectors) that overcome the limitations of current detectors and which provide personnel with continuous, reliable protection in a potentially dangerous environment. The present invention satisfies these and other needs.